In the Brothers Grimm tale “The Three Feathers,” the youngest son is called Dummling.
A king wants to determine which of his three sons should inherit the kingdom. He sends them in the directions indicated by three feathers, and Dummling appears to receive the least promising path. His feather leads to a hidden entrance beneath a trapdoor.
There he meets a frog who helps him obtain the finest carpet, ring, and bride for the king’s tests. The older brothers mock him, but the supposedly foolish son succeeds. “Dummling” is a recurring Grimm name or nickname for an underestimated younger son, not a unique personal name in the modern sense. The story is distinct from “The Golden Goose,” which also features a character called Dummling.